[Selfish Gene]

I would be inclined to agree with you Spoops and I do agree with you that the fact that white spirit Fast Offense offers 7 momentum for Youkai is a tad bit absurd. The only reason I'm not very fond of just slapping a "No this spirit doesn't exist" solution on this matter is because it just seems like a slap-on fix with no legitimate reasoning behind it. It'd be awkward for a new player to join the game and say:

Oh hey, so I'm new to the game and I'm fiddling around with possession. I've been trying to get a white spirit for Fast Offense so that I can get an extra momentum for PVE fights, but I haven't had any luck. What gives?

And if the solution to that is quite literally:

Oh yeah, we thought it was too OP in PVP so we decided to make it impossible to get that one spirit due to said reason.

I don't know, that doesn't really rub me the right way. I would rather spark a well thought out discussion and talk about potential fixes the community can think of that isn't just slapping on a white spirit ban for the skill and calling it a day. Would it be easy? Yes. But it's too easy if that makes any sense.

Edit: Also, the game already promotes and highlights the use of 1 Bonded Youkai by providing other skills and effects that benefit you if you choose to do so. Fight As One grants +30 Evade, Hit, Crit Evade, and Crit if your Bonded Youkai is near you. Synchro Summon increases both you and your Bonded Youkai's stats by 6. Offensive skills give bonus effects if you only have one Bonded Youkai as well (For example, Ritual Sword will summon the Youkai to your side). I think it's fair to say that if someone wants to only have one Bonded Youkai they're more than free to, it's just that in its current state, having many Youkai to summon with Fast Offense offers the most benefits.